Manufacture and use of ferrosoferric oxid.



cmrsn STATES HANS G0.IJJSGHISHD'JI, OF ESSEN-ON-THE-BUHR, GEBMAIIY.

MANUFACTURE AND USE OF FERROSOFERRIG 'OXID.

No Drawing.

Specification of Letters Patent. plioation filed larch 4, 1911. Serial rim-12200.

Patented Oct.- 14, 1-913.

To all whom it may concern: I

Be it known that I, Hans Gowscrmm'r,

' subject of the King of Prussia, German Empire, have invented certain new and Emperor, and resident of Essen on -the- Ruhr, in the Province of the Rhine, German useful Improvements in and Relating to the Manufacture and Use of Ferrosoferric .Oxid,

of which the following is a specification.

It has not hitherto been possible to produce directly upon'a technical scale a pure ferroso-fern'c oxid which can be advantageously used for the purposes of the art. As is well known, largaquantities of magnetic iron stone or iron ore nature, but this material usually contains a rather large proportion of gangue and other impurities. From this material it is impracticable to obtain the magnetic or ferrosoferric oxid in a pure state, even by magnetic separation since the gangue and impurities are usually so intimately distributed as to be contained even in the smallest particles which can be produced. This is true of the mechanical impurities present and also of chemical im urities which, of course, cannot be separate by magnetic treatment The natural magnetite usually contains phosphorus and sulfur. Attempts have been made to produce ferroso-fernc oxid from pur le ore (Fe O and other iron oxids, but or this purpose it is necessary to melt the material in an electric furnace and the material remains impure. And the physical form of melted and comminuted material of this kind is not as desirable as it should be for many purposes.

It has been found possible to produce a very pure ferroso-ferric oxid from iron scale or forge scales which are obtained, as is well known, in large quantities as a by-product in the rolling and'working of iron and steel;-

as in rolling rails, making wire,.etc. In the present invention, forge scale or iron scale of this character is employed.

Forge scale or iron scale consists mainly of oxids of iron but also contains a large amount of im urities; and hitherto it has been employe mostly as an addition to the charge of blast furnaces; an addition which is usually regarded, in the art, as of inferior value. The mechanical impurities of the scale chiefly consist of mill dust containing silica or sand, argillaceous materials (dirt or clay), oil, etc. Frequently the scale also contains metallic impurities such as small particles (magnetite) occur 1n of iron. The composition of scale varies greatly with the source and with the manner of production. It is however, a low grade material. In the present invention such scale is treated to free it of all impurities and to produce a uniform product containing a uniform amountof oxygen. A uniform product of this kind, free of mechanical impurities and containing a uniform amount of oxygen andin the physical form of iron scale,- is found to be particularly su'itso-called thermit mixtures; that .is mixturesof powdered aluminum or other re.- ducing metals or alloys with oxid of iron which when ignited give by interaction a pure, highly heated, molten iron.

In the most advantageous embodiment of the' present invention, the crude scale is first heated to drive off oil and water, to oxidize particles of iron present, to make the oxyen content uniform and to remove various impurities such as sulfur. should be a calcining or roastin operation. Advantageously the material is eated with an oxidizing flame. The scale is apt to contain a considerable amount of sulfur, and

which the scale was derived had been previously pickled with sulfuric acid; as is often the case. This sulfur, it is found, is entirely removed in calcinin the scale in the manner indicated. In t e calcination the organic matter (dust, oil, etc.) is also entirely. dized. .After this treatment it is advantagranular form, as is the case with com or products obminuted natural magnetite 'tained by fusion'but are in the form of fine lamellee; they retain the ,physical form of the mill scale. This physical form of the product makes it particularly suitable for employment as a component part of thermit admixtures. The scale-like particles undergo a better reaction with aluminum able for employment as a constituent of the particularly if the iron from the rolling of to obtain to 80 per cent.,

This heating removed and metallic iron is oxi-' geous to sift the scale and, usually, to subject oxid, the

powder. To make such a thermit admixture the purified calcined ferroso-ferric oxid obtained may be simply mixed with aluminum powder or other metals or alloys capable of reducing it.

What I claim is 1. In the manufacture of ferroso-ferric process which comprises calcining mill scale in an oxidizing atmosphere.

2. In the manufacture of ferroso-ferric oxid, the process which comprises calcining mill scale in an oxidizing atmosphere and purifying operasubjecting the product to :1 tion to remove impurities.

3. In the manufacture of ferroso-ferric oxid', the process which comprises calcining mill scale in an oxidizing atmosphere and subjecting the product to a purifying o eration to remove impurities, said puri ying operation comprising a magnetic separation. 4. In the manufacture of ferroso-ferric mill scale in an oxidizing atmosphere, purifying the calcined product and admixing the productwith a powdered reducing metal.

6. The process which comprises calcining mill scale in an oxidizing atmosphere, purifying the calcined product and admixing the product with powdered aluminum.

7. Amaterial comprising a substantially pureferroso-ferric oxid having substantially the composition F e 0 and in lamellar form.

8. A material comprising a mixture of pure ferroso-ferric oxld having the lamellar form of iron scale and a powdered reducing metal.

HANS GOLDSCHMIDT. L. s.]

Witnesses:

CHAS. J. WRIGHT, ALFRED 'HENKEL. 

